Process of regulating the temperature of combustion in gas-producers.



No. 829,105. PATENTBD AUG. 21, 1906. H. L. DOHERTY.

PROGESS OF REGULATING THE TEMPERATURE OF COMBUSTION IN GAS PRODUCERS. uruonxon FILED 00165. 1904.

WW w v] N0- 829,l05. PATENTED AUG. 21, 1906. H. L. DOHERTY.

PROCESS OF REGULATING THE TEMPERATURE OF COMBUSTION IN GAS PRODUCERS.

APPLIUATIOH FILED 00125. 1904.

SHEETS-SHEET 2 PATENTED AUG. 21, 1906.

H. L. DOHERTY. NG THE TEMPERATURE OF C PROCESS OF REGULATI OMBUSTION m GAS PRODUCERS. APPLIGATION FILED 001226, 1904.

4 SHEETS-SHEET 3 No. 929,105. PATENTED AUG. 21, 1906 H.L.DOHERTY.

PROCESS OF REGULATING THH'I'EMPBRATURB OF COMBUSTION IN GAS PRODUCERS. Arrnmu'mx FILED 00w. 2a. 1904.

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UNITED STATES PATENT OFFICE.

HENRY L. DOHERTY, ()F MADISON, WISCONSIN, ASSHlNOR, BY MICSNE AHSIGNM 1 h "lb, l() (fOMBUS'llON U lLllllES (JOMPANL OF NEW YORK,

Y., A (TORPORA'IION OF NEW YORK.

PROCESS OF REGULATING THE TEMPERATURE OF COMBUSTlON IN GAS-PRODUCERS.

Specification of Letters Patent.

Fri-touted Aug. 21,1906.

Agplitaiion filed October 25,1904. Banal No. 229.910.

To (all whom it mug r'mmzm'n:

Bo it known that l, HENRY L Donrnrrr, a ritizon of the United Status, and u rcsidont of Madison, in the county' of Dunc and State of Wisconsin, haw inwnti-il nn'tuii i now and useful lmprovclncnis in iroccsscs of Bern llilllg the 'lcuuwruturv of Combustion in a Gain-Producer Furnace for limiting ctort- Ovens or for other l scu. of which the following is l]. specification accompanied by drawings.

This invention rclates to a proccss for regulating tho trmpcruturc oi ronihustimi in a gas produccr furnace for heating retort-- ovensor foruthoruscs; and thcobjccts of the invent ion arc to prevent or minimize the formotion of (linkers in thc furnace und. secure a saving in tho amount of fncl required to produce a given result.

The furnmtion of (linkers dcpends on tho temperature, and thnr are formed from a pmtial rluxing or fusing; of the slag or incon'ibustibia portions of the fuel They are largely com )oscd of silicon, cairiurn, and iron It has con found from oxpcricnce that iron in tho ash of any onllAulinuQoUs fuel produces a tendency in ine fuel to rcudil form clinkcrs. The formation of clinkcn; can be obviated by maintaining tho combnbtion at a temperature lower than that required for the formation of the slug or flux. in gas-producer furnaces employed for homing rctorts in the regenerator form of cold-gins hem-n it has hitherto been customary to introducv under the gratebars or into the mass of incandescent fucl in tho furnace wutcror steam in order to rcducc the tem crature of the fuel. and thus minimize. as or as possible thc iornuition of clinkers in the bed of fuel, because these obstruct the draft through the bed and fasten thornselvcs to tho sidcs of the furnace-walls, iinpcding the proccss of combustion and pro- Vonting the maintenance of the proper tom pcraturc in. the retorts. required to carbonize the coal therein.

Tho use of watur or water-vapor to restrain the risc'ol' temperature throughout the bed of incandescent fuel isohjectionable, because there is loss of heat due to the fact that as the water must be heated and evaporated from or about Fahrenhvit to steam at the tcniporaturc at which the waste gusois or Dru nets of comlmsuon ordinarily leave the furnnce-stzick and pass into the uti||o$plic1r--- an 800 i uhrcnhcit-or o'vcr -thr-rc i a rosultlug loss of about Fuurtocn hundrcd l3. '1". il for each pound of wntcr thus ovurmrotod. This is s iuwn as follows:

Hoot rcquircd to misc one pound of water from Wtk her at 60 Fahrenheit to 212 Fahrenheit i Water at 212 Fahrenheit to strain at 212 Fuh- Tomi .7 1,4(10531 B. T. U.

Tho specific heat of tho s1 cum in the wastc products of coinhustiou at tho tonuwmturc specified is approximately .48, and in the above calculations the hoot of mnlorhorlnic and exothermic rcactions is disregarded It will be observed in the above dcicrininntion of the heat lost due to tho ovu 'ioriaiion of one pound of water no account has hoon iukcn of the amount of heat rcquircd to disussociuto the steam into its elements, hydrogcn and ox gen, which is an endothcrmic rcncthin, for the reason that the hydrogen is again burned back to steam in the combustion-chanibr, which is an oxothormio reaction, whcrcby tho same amount of hcut is givcn out as was all-- sorbcd in the cndothcrniic reaction. For this reason the endo and 0x0 thcrnml reactions balance each other and have thcroforo not been considered in this calculation.

In addition to tho loss of boat occusiolwd by the use of water 2L5 illustrutcd above them is yet a more serious objcction to its uso as a moans of provcnting the, formation of clinkors, duo to the fact that in order to reduce the temperature throughout the entire bed of fuel bclow the clinkcring-point it is necessary to introduce water in such a. largo quantity that the fuel in the immediate icinity of thc'Water-pan and drilp-plutcs is re duccd in temperature below t mt of ignit on or that tom erature which is necessary to support coin nation. The iropurtionofwm t r used per pound of fuel will vary frour thirt -throc and 0ne-third per ccnt. to one hun redpcr cont. As nconsequcnoc tho fuel is quenched, which fact may be observed by opening the cleaning-door of the furnace While in operation and noting the fact that scarcely any live or burning fuel is visible, the furnace pres nting the appearance from below of a the that is almost extinguished, while the fuel-bed, as viewed from above, shows that a high temperature exists in the upper part of the mass. The unburned fuel in the lower part of the fuel-bed is raked down, intermingled, and removed with the ashes, and is thus lost. Moreover, it has been found thus far impossible in this type of furnace to entirely prevent the formation of clinkers by the use of water and steam. If enough water is used to reduce the temperature below the clinkcring-point, there is too great a loss of heat and fuel, while the use of an insu'llicient quantity of water results in excessive formation of clinkcrs attended with their accompanying evils. In view of these conditions the customary practice has heretofore been to admit suliieient water, and, if necessary, steam in addition, so that the formation of clinkcrs will be reduced to such an extent that by thoroughly cleaning the fur nace at frequent intervals the fuel-bed will be maintained suliicicntly free to obtain the roper amount of combustion. The cleaning of the fire is generally termed "clinkering and in practice is attended with great labor and loss of fuel. During the operation of clinkcring the cleaning-door necessarily remains wide open, permitting an excessive rush of cold alr to pass up through the furnace, thus rapidly reducing the temperature of the entire structure, resulting in an alternate contraction and expansion of all the parts, which reduces an increased leakage and reduces t ie useful period of the entire structure to a term of but a few years.

This invention el'itirely does away with the use of water and steam for preventing clinkering, thus obviating all the evils attendant upon their use, and the invention consists of a process of employing carbon dioxid substantially as hereinafter fully described and claimed in this specification for regulating the temperature of combustioh in a gas-producer furnace for heating retort-ovens or for other purposes.

Suitable apparatus is shown for carrying out the process, in which A Figure 1 represents in front elevation what is termed a fulLde t-h. rcgenerator coal-gas bench having a bed of full depth. Fig. 2 represents a transverse vertical section of the bench shown in Fig. 1. Fig. 3 is a vertical longiti'dinal cross-section on the line A A. oi Fig. 2. Fig. 4 is a vertical longitudinal cross-section on the line B B of Fig. 2. Fig. 5 is a vertical longitudinal cross-section on the line (I C of Fig. 2. Figs. 6, 7, and 8 are res ectively a plan, front elevation, and side ei evation of one of the injectors which is used for the )urpose of withdrawing a portion of the products of combustion from one of the \vaste-llucs and forcing the same mixed with atmospheric air under the furnace-grate Fig. 9 is an enlarged longitudinal cross-sew tion view of a furnace provided with dri plates and watcr-pan, illustrating graphically the condition of the fuel-bed when water is used as a cooling medium; and Fig. 10 is a vertical cross-section view of the bench similar to Fig. 2, but is diagrammatical in character in order to more clearly indicate the flow of gases in the gas-bench.

In the drawings a suitable gasreducer furnace for heating retorbovens is il ustrated in which the process may be carried out. This apparatus consists of a gas-producer furnace provided with means for supplying water under the fuel-bed in accordance with usuai practice, because I wish to show how my im roved process may be substituted for the oh water process without changing the apparatus. In Fig. 9 I have illustrated graphically the condition of the fuel-bed when water is used as a cooling medium, showing how the fuel in the lower portion of the bed is quenched by the water. In Fig. 9 the lower portion of the fuel-bed is shown very much darker and blacker than the remainder of the fuel in the bed to illustrate the quenching effect of the water. This im proved process may be carried out in any suitable form of apparatus, and that shown in the drawings is by way of illustration only.

Referring to the drawings, A represents a gas-producer furnace for heating retort-ovens, in which E represents the retorts suitably supported in the oven, and (1 represents the grate-bars to support the fuel-bed D.

J is the ash-pit door, and K is the fuelchute for feeding fuel to the fuel-bed.

The space above the fuel-bed in chamber L is connected by a series of nostrils O with the secondary combustion-chamber P, to which the secondar air-supply is led through the nostrils Q. be secondary air-fines R communicate with the atmosphere at the lower portion of the furnace by means of the apertures S, controlled by the secondary air-dampers T. The secondary air-fines, as shown, are provided with horizontal iartitions U, having staggered air-fines V. hesc second ary air-fines, together with the waste-fines W, form the rccuperator, and, as shown, the waste-fines in this instance are arranged outside of the secondary flues R and are also provided with. horiaontial partitions X, havmg staggered openings Y. The waste-fines communicate with the oven in the upper porion of the bench by suitable passages Z, formed at the bathe-plates a. At the lower portion of the bench the waste-fines communicate with the stack 1) by suitable passagesc. The circulation of gases after complete combustion in the secondary combustion- IIO chamber 1 lollo ws the arrows and passes from the combustion chmnber P up and around and between the retorts B, down through the waste-lines, and out through the stack,which, as shown, is controlled byesuitebledamperd.

represents a, water-pipe provided with a nozzle], empty-in r into a. cup g, from which a ripe leads to the ri -ph1tes h. Beneath the iuoLbed is shown t e water-pan 'i. In the usual method in whichwater is used the water is kept continually flowing through the nozzlef and onto the drip-plates h, and the Witter. in the pan is replenished atfrequent intervals by suitable means. In the front elevation, Fig. l, the mouthpiece-s E of the rctorts are shown, having stand-pipes l connected thereto leading to the hydraulic main G. Peek-hole fittings ll, provided with removable plugs, are shown for looking into the oven in the upper part of the bench, and other peek-hole fittings I are rovided for inspouting and cleanin Y out ot ier portions of t H! bench. The v/'aste-flues are also vidcd with peek-hole fittings l.

in a bench of ordinary construction utilizing the water recess for minimizing clinkering atmospheric air would be admitted to the grate through the a ertures o in the front of the furnaoe provider with dampers These npertures 0 lead to the piisseges p, which proroinmunicute with the space beneath the grate. In Fig. the circulation system is shown diagrammatically with the oi'nission of the cross-partitions 1n the recuperetor.

According to this invention instead of using water and steam to reduce the temperature and prevent the formation of clinkers I introduce into the bed of incandescent carbonaceous fuel a decomposable as, preferably containin oxygen, prefer-ab y carbon dioxid,(GO,,) which may be used either alone or mixed with other gases. The carbon dioxid (CO is preferably intimately commin led at or before its introduction to the fueled with the oxygen used to support combustion, which latter is practically introduced in the form of atmospheric air. It is of course economical to lead the gaseous mixture to the fuel-bed in it somewhat hunted state, and preferably the heat should be for nished from a source of waste heat. A. portion of the \HtSllt proiilucts of oombustion may be intercepted after they have been used for heating the retorts 13 end. if necessary, after they have heated the secondary air supplied to the eonibustion-chmnber l of the furnace. This intercepted portion of the products of combustion, together with the air thus required to support conllnistion, is led beneath the grate of the furnace. The arbon (lioxid thus introduced puss-rs up through the bed of b rning fuel and is disussocinted, forming carbon rnenoxid, 0,) thus 0., 2(1). This rln-iniral disnsso motion of the carbon dioxid or endothermic l reaction absorbs heat and maintains the hem ierature of the illt'ullllt'm'vlll bed of fuel at the desired point. ]relerabl no air is admitted to the top ol' the huddled in the chamber L, because the draft is upward throu h the nostrils to the combustionchain )er. in carrying out this pl'utoss inllie gus-bonch shown in the drawings passages s are rovided in the well of the bench leading to t e waste-Hues \V, so that a portion ol the waste products of combustion may bewithdrawn from the lines, mixed with atmospheric air, and introduced benonlh the grate through the apertures 0. Any suitable means may be provided for introducing the mixture beneath the grate, as sliou'n,-iu this instance an nir-injeclor being used, the run struetion of which is illustrated in Figs. u, T, and b. This injector is preferably so con structed that it may be placed against the side of the bench and register with the upcin ings s for withdrawing the produru of ('(illlbustion and with the apertures o for inje0ting; the mixture. The injr-rtor is provided with s nozzle with which a pipe 2/ C(Hlillllllii (EttlQS, provided with u valve t. The nozzle 5 injects air into the passage it, adapted to communicate with the aperture o for the in jection of the mixture. 0 posiic the nozzle 6 is arranged a damper :r ior regulating the supply ol' air for the mixture. A constant pressure of air is maintained upon llusup ply-pipe u, and the innouut of air supplied to the niixtureisregulated by the damper .r. In carrying out the process preferably two injectors are used with a benrh ol the rharaoter described, one at each side, but one being illustrated in the drawings for the snke of cleerness.

I have discovered that the temperature throughout the entire inraiuleseent bed of fuel may be kept down to a point. at which cliukering will not occur by utdizlru: the heat-absorbing effect UUCUIIlDg in the chemical disessociation of the carbon dioxid, and this is one of the essential features of the proc- In carrying out the process the mixture of carbon dioxid and oxygen should be led beneath the fuehbed at such tonipiinuturr and the proportions of carbon dioxid, tree oxygen, and free nitrogen should be such that the fuel is kept below' the temperature at which oliukering occurs, limit being given up to the gases from the'fuel. 'lhis tonereture at which rlinkering rouuueuros to ibrin varies from about L500 Fahrenheit to about 2,300 Fahrenheit, depending upon the character of the fuel and the amount of iron and silicon therein. l luiw found that a mixture of about four per cent. ((l.,, sixteen per cent. free oxygen, and eighty per cent. free nitrogen at temperature of about 600 Fahrenheit is suitable for carrying out my improved process with At certain character of fuel which clinluirs at it high tempere- IXC lure, and another mixture of about ten per cent. ('0 ten per cent. free oxygen, and eight per cent. free nitrogen at a. tempera ture of about Tlltl" Fahrenheit has also been found suit able with another character of fuel which clinlo-rs at a much lower temperature. The higher the temperature of the gaseous mixture admitted beneath the fuel-bed the larger should he the proportion of (O in the mixture, which is necessary to keep the ten.- peratnre oi' the fuel-bed below the clinkeringpoint, I have found that the mixture of (1),, Free oxygen, and free nitrogen operates satisfactorily if injected at a temperature of from titltl Fahrenheit to about 800 Fahrenheit in which case heat. is given up to the gas from the fuel and clinkers are not forired. if the i is taken from sone source other than lhe waste products of combustion, the perccntageol' nitro cn may he either decreased or increaset from the proportions stated. If the temperature of the mixtureof air and gases su tpllt'tl to the fuel-lied is con siderahly less than the temperature of the fuel-bed the gases will in themselves, as well understood, ell'ect the physical absorption of some heat. from the fuel-bed.

In an ordinary gas-producer furnace the temperature of incomplete combustion is usually carried on at approximately from LSOU to 2,00t) Fahrenheit, while the temperature of complete combustion carried on in the combustion-chamber P, where the secondary air-supply is admitted, will usually be considerably higher, frequently 2,500 Fahrenheit or more. if the gasproducer is used to heat. rctorts, as illustrated in the drawings, the temperature of the retorts should be about 2,3500" Fahrenheit, and the waste products of combustion after circulating around the retorts enter the top of the recupcrator at about 2,000 Fahrenheit to about 2,20U Faln'enhcit. These products of combustion are cooled down in the rccuperator before entering the chimne to about 800 Fahrenheit to about 1,000 l ahrenheit, and a portion of said products are intercepted at some suitable point after heating the rctorts and mixed with air which is at atmospheric temperature, so that the mixture injected will range about 600 Fahrenheit to aoo l ahrenhoit. If the gas-producer is not use. for heating-retorts, the products of incomplete combustion may be first led to ancngine or other suitable device in order that they may be deprived of a portion of their heat and be suitably reduced in temperature before their introduction into the incandescent fuel. As the appearance of the tiro-bed furnishes a direct guide to the temperature that is being maintained therein, it also furnishes the best guide for ropor tioning the quantity of (.(hadmitte to get the lowest temperature desirable, it being preferable to admit a little more rather than a little less CO2.

Another feature of the process resides in the fact that carbon dioxid on account of it low thermal capacity absorbs but little heat until the temperature of disassociation is reached, which is far in excess of that; at which the fuel becomes extinguished With the use of water, however, a large part of the heat is absorbed at a. temperature of 212 Fahrenheit while the water is passing from water to steam, which operates to produce a quenching effect on the fuel, as hcreinboforo stated.

I have illustrated the furnace provided with drip-plates and water-pan for two reasons -i. (a, to show that the process may be carried outin furnaces as now constructed with a minimum of alteration and expense, and, secondly. to show that my new process may be used, if desired, in connection with the old water process, so that a gas of lower hydrogen content may be )rotluced than in the old process if this shou d for any reason be deemed desirable. It has been found in actual practice with my improved process that the saving of fuel amounts to twenty per cent. and over with average fuel.

By comparison with Jacob Reese's patent dated Dec-ember H5. W84. wherein is set forth a process which consists in returning some of the gases from directly above the bed of fuel through a cotnlnlstion-clnunher and back under the tire at an excessively-high'tempe 'ature. stated to be gcnerali sulliciently high to fuse the slag and cause it to llow in a liquid conditionput of the slag-vent, one point of novelty of my process--to wit, limiting the temperature to one at which clinkers will not even be formed to any considerable amount, much less fused vill be apparent; so, also,. 'lodd patent of December .24, 1872, which describes a. process for treating gases and fumes to convert them while still highly heated and in which it is claimed the productsof combustion was through and heat a translormefl" will aid in showing the same. Again, a. British provisional patent to Kidd, No. 3,174 of 1874, though apparently abandoned without being completed, sets forth that products of combustion are forced through a lower layer of fuel in a second or decomposing chamber and soon raise the fuel therein to a white heat under conditions quite at variance with the present invention. This also shows the wide distinction between the productions of high temperatures and the limitation of the fire-bed temerature which I accomplish. Indeed, the itcrature of this art shows that one Blanchard. has even proposed to produce the most, intense heat attainable by introducing carbon dioxid and air at various parts of an inclosed furnace and has stated that the upper portion of the fuel on the grate is thercb raised to an intense incandescent heat su'i' ficient to permit the gases admitted below the grate to pass through without cooling the tire below the desired intensity. So, also, in smokewonsuining processes it has been suggested frequently that some of the unburned products, with of" coursecarbon dioxid, be returned through the fire-bed to produce an intense and more com ilete combustion. Here it will be seen that utterly ditlercnt ob jects and processes are accomplished. Consideration of such processes or supposed processes will show that my present invention is radical. it is distinguished widely therefrom by the fact that I combine with a heat economy, impossible in the use of water or steam for cooling the bed of fuel, the absolute and easy control and limitation of the temperature in a remarkably even manner below that at whith clinkers are formed in objectionable quantities. In short, 1 lower the temperature of the fuel-chamber with a great increase instead of a decrease of economy.

As dillercnt qualities of coal and coke vary considerably in respect to the tendency to produce clinkers and in respect to the temperatures at which clinkers will be formed, it will be evident that fuel that less readily forms clinkcrs may be burned at a higher temperature under the present process either with less pro )ortion of carbon dioxid introduced or with higher temperature of the air and gases admitted.

One great cause of clinkers is that under the old method thin places or draft-holes occur in the fuel-bed, and consequently the rush of air through this path of low resistance causes localized rapid combustion, producing llllinsc temperature and rcsultin in the rapid formation of clinkers. By t. e use of my process an opposite effect is produced, becauscin case there should occur a thin spot or path of low resistance to the passage of the draft the carbon dioxid present would reduce the temperature and rate of combustion at this point, and eonse uently the path of low resistance would grar ually disappear.

The principles of nature that underlie the recess SW'II] to he that the reduction of car- )on dioxid is at: endothermic reaction that absorbs lu-at chemically, and the introduc tion of a large volume of gases that do not support combustion, with the oxygen at a temperature much below that of the lirc-bed, absorbs beat )h-ysically, while, on the other hand: the oxidizing of the carbon of the fuel to carbon monoxid (much more it to carbon dioxid) within th fuel-bed by theoxygcn introduced evolves heat. Some heat of course is lost by transmission and radiation throu 'h the l'urnacewalls; but this should not w colisidiliililo and is notably less with my lower teniperimure. The temperature seems to be maintained constant (so far as horiand the heat evolution, on the other hand,

and the process is to a large degree sell-regulating, as any increase in icnuwratu'rc at any part of the fuel-bed is opposed by an incrc sod reduction'of carbon diox d at that spot. It is probable that less total carbon ioxid escapes from the bed than enters it, which would mean that a very considerable amount of heat energy is taken up in the ondothcrmic reaction oi reducing some of the carbon dioxid, in which event all the oxygen of the air passing through the bed may be considered and T1 rured as converted .into carbon monoxid. i so, we have the evolution of heat by combustion of the oxygen to carbon inonoxid set against all the physical losses and against thc chemical loss of all the net reduction of carbon dioxid to monoxid. As this effect increases with the temperature, it follows that there is one stable mean temperature for the fire-bed which will be reached and maintained for each particular proportion of gases admitted, (other conditions being alike.)

While the temperature at which clinlrcring occurs is not an absolutcly definite tempera turecvcn for the same grade of fuel, i use the expression clinlwring tcmpcraturc to designate a tempt-nature which is very much less -than that at which the linkcrs or slag; an be entirely fused and which does not exceed that at which an ol'ijcctionable amount of (linkers will be formed. It is sullicienlly definite under any given conditions to be clear to an engineer.

It will be seen that to a certain extent the temperature of the admitted gases and the quantity of CO iniroduccd arc interchangeable factors, for the higher the temperature of the air and gas supplied the larger pro portion of carbon dioxid will be required to properly limit the temperature, and vice versa. Furthermore, it will be understood by engineers that time, as well as tempcrature, is afactorin the reductionof the carbon d oxid to monoxid in the fuel-bed. There fore with an increased velocity of the gases in the fuclbcd or with decreased thickness of fueLbcd a somewhat greater proportion of carbon dioxid is necessary than with lower velocitie and th cker lucl-bcds. Moreover, it will be seen that the present invention can be advantageously used in many dill'crent ways as, for example, in a large lucl-bed dill'ercnt proportions of carbon dioxid may be introduced at dilicrcnt parts lo maintain different temperatures.

As it is evident that the present process might be used by parties thinking to evade my patent in conj unction with some water or steam, so as to enable them to use less carbon (fl oxid, but for the same object and in the same way as herein described, it is clear that in the broader of my process claims I. do not mean to define the invention by the propor tions except as the proportions can be and are in practice determined by the temperature producedfl'or by means of that temperature th operator is directly informed as to whether to increase or to decrease the supply of carbon dioxid.

This application is for the same invention as that set forth in my copcnding appl cation, Serial No. 187.31 tiled December 31, N03, with additional deta ls.

What I cla m. therefore, and desire to se' cure by Letters Patent as the characteristic feat ures of my invent on. are the following:

1. The hcrein-described process which consists in making producer-gas from a deep bed of fuel with a draft-current containing free oxygen and a neutral diluent fixed endothermicallv-reacting gas in predetermined proportion and regulating the temperature of the draft current with reference to the endothermic capacity of the gas and the exothermic power of the oxygen in such manner as to maintain the temperature in the producer at a point where the fuel will burn with sub- Stantial conuiileteness to an ash.

2. The herein-described process which consists in making produccrgas from a deep bed of fuel with a draft-current containing products of t'UIHhUSIiOH and free oxygen in predetermined proportions. and so regulating the tem erature of said products with reference to t ieir richness in carbon dioxid, and the exothermic power of the free oxygen as to maintain the hottest portions of the fuel-bed below the (tinkering-poi]it of the particular kind of fuel employed.

3. The herein-described process which consists in makipg combustible in a deep bed of fuel with a draft-current of endothermically-reacting fixed gas and free oxygen and so regulatin the temperature and composition of the draft as to maintain the fucl-bcd substantially free from obstruction by slag.

4. The herein-described process of making combustible producer-gas which consists in conducting combustion within a deep bed of fuel by an artificially-accelerated draft-current of free oxygen and an endothermicallyreacting fixed diluent gas, so regulated with reference to the temperature and richness of the diluent and the proportion which said diluent bears to the free oxygen, as to maintain the temperature of the producer below the slugging-point of the fuel.

5. The herein-described process of gasmaking which consists in operating a gasproducer under artificially-accelcrated draft and suppressing the tendency to tempera- .ture rise within the fuel-bedby the employment of a fixed gaseous endothermieally-reacting agent present in predetermined ratio to the combustion-supporting oxygen, and

whose temperature is such with reference to its endothermic capacity as to avoid objectionable slagging of the fuel.

ti. The herein-described process of making combustible producengas, which consists in conducting combustion within a deep fuelbed by means of air and carbon dioxid, and separately regulating the roport ions of said ingredients so as to avoid the objectionable shagging of the fuel, and coi'ulucting said gas unburned to the point of use.

7. The hcreinbeforc- .lescribcd process of nuilcine; combustible producer-gas which consists in conducting combustion within a deep fuel-bed by means of air and carbon dioxid, regulating; the proportion between the quantity of air and carbon dioxid introduced into the producer, and regulating the amount of such mixture of air and carbon dioxid so as to avoid objectionable slaggingof the fuel and conduct ing said gas unburned to the point of use.

8. The hereinliefore-described process of making combustible producer-gas which consists in conducting combustion within a (lee fuel-bed by means of air and carbon dioxid, and re; :ulatin,% the proportion of each with respect to the amount of coal to be consumed in the producer and its quality so as to avoid the objectionable slaggmg of the fuel and conducting said unburned to the point of use.

9. The hereinbefore-described process of making combustible producer-gas which conin conducting combustion Within a doc fuel-bed by means of air and carbon (iiOXit. and separately re ulating the amounts of said ingredients to fix the proportion between them so as to avoid objectionable slagging of the fuel, and conducting said gas unburned to the oint of use. 4

10. I he herein-described process which consists in making producer-gas from a deep bed of fuel with a draft current containing oxygen, nitrogen, and carbon dioxid, and proportioning the carbon dioxid with reference to the temperature of the draft and the slagging qualities of the fuel to determine and maintain the tern erature equilibrium occurring between t to heat produced in the fuel-bed by thereaction of the free oxygen. and carbon mainly to produce carbon monoxid and the heat absorbed by the endothermic and physical actions at a temperaturn below the objectionable siagging or clinkering temperature of the fuel.

11. The herein-described process of making combustible producer-gas which consists in conducting combustion within a deep fuelbed by means of oxygen, nitrogen, and carbon dioxid, and proportioning or regulating the ratio of carbon dioxid and oxygen so as to avoid objectionable slaggiug of the fuel by restricting the temperature of equilibrium occurring between the heat-producing combus- IDS tion of the oyxgen mainly to carbon monoxid, and the physical and endothermic heatabs rbing act-ions and conducting the combustible gases evolved to the point of use.

12. The herein-described process of making combustible producer-gas which consists in (ondueting combustion within a deep fuelbed by means of air and earbon dioxid, and in regulating and controlling the proportions of said ingredients so as to EtVOil objectionable slugging of the fuel and conducting said gas unburned tothe point of use.

13. The herein-described process of regulating and controlling combustion in making producer-gas whirh consists in conducting combustion of oxygen and mirbonaeeous fuel mainiy to produce earbon monoxid in the presenee of rarbon dioxid, and in nmintain ing'the temperature emiilibrium occurring between the lH'ttUPlOllUClXlg and the heatflbSOTl'JiHQ: aetions in the fuebbed at a temperature below the objectionable (.linkering temperature of the fuel by introducing to a deep bed of the fuel a draft essentially of air and produets ol' eombustion and by so regulating and iroportioning the ratio of produets of com mstion and air with reference to the temperature of the draft and the slagging qualities of the fuel, substantially as deseribed, as to limit the temperature as aforesaid.

14. The irnprow-ment in the art of making producengas whi rh consists in emuluoting and regulating the eembust ion and in equalizing the distribution of temperature and preventing exressive temperature locally in arts of the fuel-bed by supprn'ting the comuustion by a draft eontaining air and products of combustion in a determinate ratio and at a determinate temperature, substantiallyus described, such that the equilibrium between the heat-producinq actions and the heat-reducing actions will occur and be maintained at a temperature below the. ob jeetionable siagging or elinkering temperature of the fuel and whereby the loeal rise of the temperature at any point in the bed is prevented. by the inereased endothermic effeet of the (atrium dioxirl present.

15. The improvement in the art of making produrer-gas which consists in conducting and regulating the eombust ion and in equalizine the distribution of temperature to prevent excess looally in parts of the fuel-bed by supporting the eombustion by a draft containing air and products of combustion in a determinate ratio and at a determinate temperature, the pereentage ofrarbon dioxid present being,' not less than five per cent. nor more than iii'teen per rent.

16. lhe improvement in the art of making prmhu-er-gas whieh consists in eondueting and regulating the combustion and equalizing the distrilmtion of ternperaturt to pre than is hitrodueeii below it, wl'iereb sub-:1. an-

tially all the free oxygen introdured i:-. -on-- Verted into Carbon monoxid with some at tendant reduction of the carbon dioxid that is introduced.

17. The improvement in the art of making producer-gas which consists in eondoeting and regulatin the eomb'ustion and equalizing the distribution of temperature to pre vent excess locally in parts of the i'uet and by supporting the combustion bra dra t .'--l taining air and prodn its of ronibmatiob wit h-- out adding steam in a determinate rat n and at a determinate temperature, the perv. mp3 of r-arbon dioxicl present being not lost than five per cent. nor more than liiteen pm rent the percentage of carbon dioxid being sun-h in Ir-speet to the tempera ture of the draft as to restrirt the temperature of the l'ne'i-bed be low the objectionable eiinlo-rin i temperature and less earbon dioxid being; giv n oil above the fuel-bed than is intrr-ttured beiow it, whereby substantiaily ail tie tr e oxygen in-- trodneed is ronverted into lilli iln Haw-Md with some attendant rriiu vlion of iilv lf dioxid that is introdured.

18. The herein wiesoribed prom-9* Aiw consists in making pro hu-er ;:as uitlfo a deep bed of fuel with a lr:lli -1l1'ren o taininp; l'ree oxygen and pr durts oi 1. Low. .w tion strong in carbon dioxid as tzompzeoii with what oreurs in metailurgiral to: or tf t at a temperature suitii-ient to tHtJlll ri'w' i of the produeerfrom high iempei'aturevane-a.

consists in making produrel gas witbm a deep bed of fuel, burning said iuei with substantial completeness to an ash by the em ployment of an artiticially-aem-ierated draftenrrent eontaining air and iurnaeegases strong in rarbon dioxid as oompared with those. in metallurggieal tumours and retaining the temperature of lurnare gases except for the natural loss by radiation, and in its tlues through which gases are drawn, the proportion of said products being: sutl'irieni to maintain the temperature of the prodtlter below the slagging-point of the Fuel therein by the cooling action of said produet for substantially the purposes set Forth.

20. The Herein-ileseribed ploeess of making and using produeer gas which consists in lIO burning said gas in a furnace in the usual manner with a subhmntiai excess of air to souure cumplvio combustion, wnducting 00mbustion within u. dwp body of fuel with a draft-current (-nntuining the products 0f combustion from said furnace, of u richness l in carbon djgxid exceeding six per vent. and at ,& tenlpel'at re when mixed with the air sufficicnt to m intain the tempvrahu'e Ll tlupmduver boluw thv sluggingqmint 0f the fuel therein.

In trmlmuny whvrnnf l have sIgnml this 5pm Hi1 :1 Lion in tho pxv enuc ui two subscribmy; \ratm'ssvs.

HEXH Y L. DOIIERTY.

'ituvssvs: 

